The invention relates to a gas valve unit for setting a gas volume flow supplied to a gas burner of a gas appliance, in particular a gas cooker, the gas valve unit having a valve housing and an actuation pin for setting an opening cross section of the gas valve unit and an additional shutoff valve, and a movement of the actuation pin being able to be transferred to the shutoff valve by means of a linearly displaceable connecting element.
Gas valves of the type mentioned with a shutoff valve are frequently referred to as safe gas valves. A knob is generally positioned on an operating segment of the gas valve unit and can be accessed manually by an operator of the gas cooker. The opening cross section of the gas valve unit is generally set by rotating the actuation pin. The shutoff valve can be opened by the operator by axially displacing the actuation pin by pushing on the knob.
The axial movement of the actuation pin is transferred to a linearly displaceable connecting element. This transfer of the movement of the actuation pin to the connecting element can take place directly or indirectly, for example by way of a facility for deflecting the movement direction. The connecting element is in direct or indirect contact with a shutoff element of the shutoff valve. An axial movement of the connecting element in the direction of the shutoff element allows the latter to be raised from a valve seat, thereby opening the shutoff valve.
The shutoff valve generally also has a magnetic unit, which can hold the shutoff element in the open position, when the shutoff element has been moved into this open position manually by pushing the valve pin. The magnetic force that can be generated with the magnetic unit is however not of sufficient size to move the shutoff element from its closed position to the open position. The magnetic unit generally contains a wound coil, which is connected to a thermocouple disposed in the region of a gas burner. The electric voltage generated with the thermocouple brings about a current flow through the coil of the magnetic unit, thereby generating a magnetic force which holds the shutoff valve open, while a gas flame is burning at the gas burner. When the gas flame is extinguished, the shutoff valve closes automatically and can only be opened again manually by pushing the actuation pin.
Gas valve units of the prior art have the problem that pushing the actuation pin allows the shutoff element to be moved in the opening direction until it comes up against the magnetic unit. If the actuation pin is pushed in with great force, it can cause the shutoff element to change shape, which may impair the function of the shutoff valve. In particular it is possible that the magnetic unit can no longer hold the shutoff element with its changed shape in the open position because there is too great an air gap between the shutoff element and the magnetic unit due to the shape change.